The famous Ring Nebula (also catalogued as Messier 57, M57 or NGC 6720) appears in the northern constellation of Lyra. It is a prominent example of a planetary nebula. This is a shell of ionized gas expelled into the surrounding interstellar medium by a red giant star, which was passing through the last stage in its evolution before becoming a white dwarf.
Read more about Ring Nebula: History, Observation, Properties
Famous quotes containing the word ring:
“I like well the ring of your last maxim, “It is only the fear of death makes us reason of impossibilities.” And but for fear, death itself is an impossibility.”
—Henry David Thoreau (1817–1862)